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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

The illegal exploitation of certain marine species as a form of environmental crime in the Western Cape

Herbig, Friedo Johann Willem 25 August 2009 (has links)
Conservation criminology as a derivative of environmental criminology is considered in this dissertation through a strategic/empirical investigation of the illegal exploitation of a cross-section of certain, essentially fiscally attractive marine resources, as a form of environmental crime in the Western Cape province. Through primarily qualitative and quantitative interviewing techniques, augmented by the application of a survey questionnaire, significant and pragmatic insight was obtained from knowledgeable functionaries. The study elucidates the purview and dynamics of the marine crime phenomenon by focussing specifically on issues such as modus operandi, crime scenes, causation, operational efficacy, and social/biological repercussions. Deficient policing capacity and concomitant lack of deterrence, compounded by institutional limitations, emerge as fundamental proclivities impeding proficient marine resource conservation. It is envisaged that this study will broaden the frontiers of marine crime knowledge, contributing not only to the implementation of effective mitigation programmes but also to enriching the criminological discipline as a whole. / Criminology and Security Science / M.A. (Criminology)
62

Spatial ecology of marine top predators

Jones, Esther Lane January 2017 (has links)
Species distribution maps can provide important information to focus conservation efforts and enable spatial management of human activities. Two sympatric marine predators, grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina), have overlapping ranges but contrasting population dynamics around the UK; whilst grey seals have generally increased, harbour seals have shown significant regional declines. A robust analytical methodology was developed to produce maps of grey and harbour seal usage estimates with corresponding uncertainty, and scales of spatial partitioning between the species were found. Throughout their range, both grey and harbour seals spend the majority of their time within 50 km of the coast. The scalability of the analytical approach was enhanced and environmental information to enable spatial predictions was included. The resultant maps have been applied to inform consent and licensing of marine renewable developments of wind farms and tidal turbines. For harbour seals around Orkney, northern Scotland, distance from haul out, proportion of sand in seabed sediment, and annual mean power were important predictors of space-use. Utilising seal usage maps, a framework was produced to allow shipping noise, an important marine anthropogenic stressor, to be explicitly incorporated into spatial planning. Potentially sensitive areas were identified through quantifying risk of exposure of shipping traffic to marine species. Individual noise exposure was predicted with associated uncertainty in an area with varying rates of co-occurrence. Across the UK, spatial overlap was highest within 50 km of the coast, close to seal haul outs. Areas identified with high risk of exposure included 11 Special Areas of Conservation (from a possible 25). Risk to harbour seal populations was highest, affecting half of all SACs associated with the species. For 20 of 28 animals in the acoustic exposure study, 95% CI for M-weighted cumulative Sound Exposure Levels had upper bounds above levels known to induce Temporary Threshold Shift. Predictions of broadband received sound pressure levels were underestimated on average by 0.7 dB re 1μPa (± 3.3). An analytical methodology was derived to allow ecological maps to be quantitatively compared. The Structural Similarity (SSIM) index was enhanced to incorporate uncertainty from underlying spatial models, and a software algorithm was developed to correct for internal edge effects so that loss of spatial information from the map comparison was limited. The application of the approach was demonstrated using a case study of sperm whales (Physeter macrocephalus, Linneaus 1758) in the Mediterranean Sea to identify areas where local-scale differences in space-use between groups and singleton whales occurred. SSIM is applicable to a broad range of spatial ecological data, providing a novel tool for map comparison.

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